Add CI

.gitlab-ci.yml

+stages:
+  - build-all
+
+build-all:
+  stage: build-all
+  script:
+    - echo "Common build for everyone"
+    - mkdir ${CI_PROJECT_DIR}/products
+    - mkdir -p ${CI_PROJECT_DIR}/products/rascil
+  artifacts:
+    paths:
+      - ${CI_PROJECT_DIR}/products
+